Propeller.



. w. B. a G. 0. MAXWELL & E. BUGKMAN.

' PBOPEL LEB. APPLIOATIOI 1ILED OUT. 12, 1907.

Patented Dec. 6, 1910.

1 given the same reference numbers.

' body n the forward end withentering e iT133) s AWENT OFFICE.

WILLIAM B. MAXWELL, e'novnn c. MAXWELL, Ann EDWARD new 101m,- N. Y.

BUCKMAN, or

IPBOPELLER.

Specification of Letters Patent.

Application filed October 12, 1907.- Serial I No. 397,090.

Patented Dec. 6, 1910.

To all whom it may concern:

Be it known that we, WILLIAM B. MAX- WELL, Gnovnn C. 'MAXWELL, and EDWARD BUOKMAN, citizens of the United States, and residents of the .city of New York, county of Queens, and 'State of New York, have in-.

vented certain new and useful Improve ments in Propellers, of which the following is a specification.

Thls invention relates to an em roved form of propeller which is adapted or use given amount of power 'used in rotating the 4 same. To accomplish this result we have provided 'a new and novel form of construction of propeller blade which will be more particularly pointed out hereinafter in con-- nection with the illustration shown in the accompanying drawings.

In the several views like parts have been Figure 1 is an end view of a propeller emour invention. Fig.. 2 1s a plan view 0 Fig. 1. Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2.

At 1 and 2 we have shown a pair of cooperating blades which are each "rovided at es 3 and 4, respectively, which are prefera ly curved slightly forward at the outer portion and at this point have their operating surfaces extending forward in the direction of rotation and disposed substantially perpendicular to the axis or shaft 5 of the propeller'so that'in entering the water all impact or sudden blow, which would be caused if the operating surfaces on these entering edges were at an angle, with the direction of rotation, is avoided. Starting from the point slightly in the rear of these advancing edges 3 and 4 the operating surfaces at their outer circumference begin slight curvatures which gradually merge into curves which are substantially spirals extending to the rear end of the blades. The leading end of-the blade, as will be seen in Fig. 1, overlaps the following end of the opposite blade, and thus any loss in propelling power is revented and a continuous thrust is provlded, as the leading end of one blade advances in the waterjust blade recedestherein.

before the following end of the opposite Referring to Fig. 3, it will be noted that all abrupt change in the operating surfaces of the blades is avoided and a smooth continuing surface is provided from the circumference. of one blade to, the circumference of the adjoining blade. This not only provides a moreeflicient operating surface but allows the water to pass smoothly and freely over the surface of the-propeller as the same is rotated. At this point it may he noted that the term progressing is meant the'forward or front surface of the blade, and the term retreating is intended to describe the rear face thereof.

The practical utility of this construction has been demonstrated in actual use and it has been found that not only does a propeller with this form of construction ad- Vance and recede in the water without producmg an com-motion but a eatly increased e ciency in the propel ing power and resulting increase in the speed of the. boat is obtained with the same amount of driving power than it has been possible to obtain with any of the well known forms of propeller blades which have been tested in connection therewith. It is thus believed that on account of the features of construction above described a perfect cotiperation of the two blades of the propeller is obtained and a smooth operation of the same against the water .is produced which produces the most efficient results.

As many changes could be made in the above constructionv and many apparently widely dilferent embodiments of our invention designed without departing from the scope thereof, we intend that all matter con- 'tained in the above description orshown in the accompanying drawings shall be inter- 'preted merely as an illustrative embodiment of our invention and not in a limiting sense.

What we claimis 1. A propeller comprising a pair of blades having their circumferences disposed in' the form of spirals from their leadingedges to their following edges, the progressing faceof one blade and the retreating face of the other merging into *a continuous curve which extends from the leading to the following. edges respectively of said blades. 2. A propeller comprising a pair of spirally disposed blades, each of said blades 10 of the other.

v begsi having a portion of its surface contiguous to I Signed at New York in the eountj of New its leading edge disposed in a plene erpen- York and Steteof New 'York'thi s'26th datyi dicular to the axis of rotation of sei blades of Sept,, 1907.

and then mergin gradual into a surface v v d I 5 curving rearwarfiy from sail. erpendicular 1 plane to its followin edge, t e circumfer- EDWARD BUCKMAN.

ence of each of said -b ades describing an arc of more than 180 whereby the-leadmg edge Witnesses:

of each blade overlaps the following edge LEWIS J. Doom'm'm, a

B. W. CoULnocK. 

